Which Materials Reflect Infrared? What "Black" Looks Like Through a Near-Infrared Camera
In short
• A material that looks black to the eye is not necessarily black in the near-infrared (NIR). Black clothes, black fabrics, black anodizing and ordinary black paints reflect NIR light well.
• Whether a material reflects infrared depends on the material, not the color. Materials that contain carbon also absorb NIR light well.
• To control reflections around infrared cameras and sensors, choose a material whose reflectance stays low into the NIR.
Hi, I'm Teppei from the new-products team at ANSOKEN.
One of the key features of our FINESHUT series of anti-reflection materials is that it also absorbs near-infrared light. In this article we look at what near-infrared light is, how black materials look through an infrared camera, and which materials reflect infrared and which don't, using photos and measured numbers.
What is near-infrared light?
The light our eyes can see (visible light) covers wavelengths of roughly 380 to 750 nm. The short 380 nm end looks violet and blue, and the long 750 nm end looks red. Wavelengths longer than 750 nm are infrared.
Starting from the side closest to visible light, infrared is divided into near-infrared (750 to 2500 nm), mid-infrared (2500 to 4000 nm) and far-infrared (4000 nm and above). This article is about near-infrared.
We cannot see infrared light. Digital camera sensors, however, respond to a wider range of wavelengths than our eyes, so they also pick up near-infrared light. That is why most cameras have an IR-cut filter in front of the sensor, to make the image closer to what we see. How much is cut, and at which wavelengths, depends on the manufacturer, and some cameras capture NIR more easily than others (Fujifilm's X-Trans CMOS sensors, for example, seem to pick it up quite readily).
We have a camera whose IR-cut filter has been removed and replaced with a filter that blocks visible light (IR76). Let's use it to see how black materials look in the near-infrared.
Through an infrared camera, a black fleece turns white
On a sunny early-spring day, a man suddenly appears... It's me.
I'm wearing a Kawasaki cap and a black fleece from a budget clothing store. All my own clothes. Clearly a fashion expert.
Jokes aside, this photo was taken with a regular digital camera (Fujifilm X-H1). In my left hand I'm holding a rectangular strip of FINESHUT KIWAMI, but it blends into the black fleece and is hard to see.
Now here's the infrared photo, taken at the same time!
Look at that. The fleece and cap, which absorbed visible light, reflect near-infrared light so strongly that they turn bright white. The plants behind me are white too, and the photo looks nothing like the first one.
Only the FINESHUT KIWAMI strip in my hand is clearly black. It absorbs near-infrared light as well, so it stays just as black as before.
Side by side in monochrome, the difference is obvious. The fleece was 100% polyester. In this way, many black synthetic fabrics absorb visible light well but still reflect near-infrared light. FINESHUT, on the other hand, has carbon built into its raw material, so it keeps NIR reflection low as well.
Materials that reflect near-infrared, and materials that don't
So how much near-infrared light does each black material reflect? We compared our products and black anodizing, which is widely used in optical equipment, at commonly used wavelengths.
| Material | 550 nm (visible) |
850 nm | 940 nm | 1550 nm |
|---|---|---|---|---|
| Black anodizing (reference) | 5.4% | 65.7% | 74.5% | 87.6% |
| Musou Black Fabric KIWAMI | 0.10% | 17.4% | 37.0% | 22.0% |
| VL Flock Sheet | 0.29% | 8.7% | 9.1% | 45.9% |
| Musou Black Paint (airbrushed) | 0.56% | 1.3% | 1.9% | 11.7% |
| FINESHUT SP | 1.16% | 1.19% | 1.23% | 1.37% |
| FINESHUT KIWAMI | 0.70% | 0.70% | 0.72% | 0.75% |
| FINESHUT KIWAMI XX | 0.52% | 0.55% | 0.56% | 0.61% |
| IR Flock Sheet | 0.26% | 0.27% | 0.30% | 0.47% |
Representative total hemispherical reflectance (angle of incidence 8°), measured by an external testing laboratory. Not guaranteed values. Bold rows stay low into the NIR. Black anodizing is not our product; we obtained a part and measured it under the same conditions for reference.
850 nm and 940 nm are common wavelengths for infrared LED illumination, face recognition and time-of-flight (ToF) distance sensors. 1550 nm is used in LiDAR and optical communications.
Musou Black Fabric KIWAMI, the blackest material here to the eye (0.10% at 550 nm), still reflects 37% at 940 nm. VL Flock Sheet reflects 8.7% at 850 nm and 46% at 1550 nm. Both are excellent for applications viewed by the eye (photo backdrops, darkrooms and so on), but they are not suited to infrared applications. FINESHUT and IR Flock Sheet, in contrast, keep almost the same reflectance from the visible range into the near-infrared.
Black anodizing is common on lens barrels and parts in optical equipment, but it reflects 60 to 90% of near-infrared light. For details, see Black Anodizing Reflects Near-Infrared Light: A Hidden Source of Stray Light.
Comparing anti-reflection materials with an infrared camera
At the request of our readers, we also compared optical anti-reflection materials, not just a budget fleece. From left: a commercially available PET film with a black anti-reflection coating (think of it as a typical anti-reflection treatment for optical equipment), VL Flock Sheet (a flocked fabric), and FINESHUT KIWAMI. The top photo is in visible light; the bottom one is from a near-infrared camera sensitive from 760 nm.
All three look black in visible light, but in the near-infrared only VL Flock Sheet turns light gray. The chart below shows their reflectance from the visible range to the near-infrared (1500 nm).
Representative total hemispherical reflectance (angle of incidence 8°), measured by an external testing laboratory. Not guaranteed values. Measured from 250 to 2500 nm in 5 nm steps; 250 to 1500 nm shown, plotted every 25 nm. The PET film is not our product; we obtained it and measured it under the same conditions for reference.
VL Flock Sheet stays below 0.5% across most of the visible range, but its reflectance rises sharply from around 700 nm. It is a well-proven material for darkrooms, but please note that it does not work in the near-infrared. FINESHUT stays almost flat into the NIR.
Controlling reflections around infrared cameras and sensors
Because near-infrared light is invisible, unexpected reflections are easy to miss. In applications like the ones below, black surfaces inside or around the equipment can reflect NIR light and cause noise (stray light) or false detection.
• Machine vision and image inspection (foreign-matter detection, semiconductor and IC inspection)
• NIR cameras for face and iris recognition
• Distance sensors such as ToF sensors and LiDAR
• NIR spectroscopy for composition analysis (food, agriculture, pharmaceuticals)
• Astronomical observation and darkrooms for satellite testing
Typical places to treat are the inside of lens barrels and the area around lenses, the inner walls of sensor housings, and the background and fixtures behind the object being imaged. Materials that stay low into the NIR can be chosen by form:
| How you use it | Material | Best for |
|---|---|---|
| Lay it or stick it | IR Flock Sheet | Backgrounds, darkrooms, inner walls of housings. The lowest values in the table. |
| Make parts from it | FINESHUT | Places that need some thickness, and die-cut parts. 0.5 to 1.4% at the wavelengths in the table. |
We can also cut these materials into finished parts. See Laser Cut Service and Custom Non-Reflective Parts Made from the World's Blackest Light-Absorbing Materials.
Why black materials reflect near-infrared light, and how to make a material that absorbs into the NIR (surface structure, dyes and carbon), is explained in Why Black Materials Reflect Near-Infrared, and 3 Ways to Build a True NIR Absorber.
FAQ
Q. Does a black material also absorb infrared light?
A. Not necessarily. Many black clothes, black fabrics, black anodized parts and ordinary black paints look black to the eye but reflect near-infrared light strongly. In our measurements, black anodizing reflected 74.5% at 940 nm, and even Musou Black Fabric KIWAMI, the blackest of these to the eye, reflected 37.0% at 940 nm.
Q. Is there a color that does not reflect infrared?
A. Whether a material reflects infrared depends on the material, not on its color. Materials that contain carbon also absorb near-infrared light well. Our FINESHUT series and IR Flock Sheet keep almost the same low reflectance from the visible range into the near-infrared.
Q. Can I use black anodized parts with infrared light?
A. Be careful. Black anodizing reflects about 5% of visible light, but 65.7% at 850 nm and 87.6% at 1550 nm. In systems that use infrared light, it can become a source of stray light.
Q. What should I use to control reflections around an infrared camera?
A. Use a material whose reflectance stays low into the near-infrared. To line a large area or a darkroom, use IR Flock Sheet. For parts that need thickness, or die-cut parts inside equipment, use FINESHUT.
Q. Can VL Flock Sheet or Musou Black Fabric KIWAMI be used for infrared?
A. We do not recommend it. Both are extremely black in the visible range, but their reflectance rises from around 700 nm and they reflect near-infrared light well. They are made for applications viewed by the eye or a regular camera, such as photo backdrops and darkrooms.
Finally
Near-infrared light is used more and more: non-destructive inspection of food, finding defects that the eye cannot see, and sensing with night-vision cameras for automated driving. Anti-reflection materials that also work in the near-infrared, however, are still hard to find. Our NIR-capable materials are effective and easy to handle, so please give them a try.
To finish, here are two photos of a shrine near our office. Can you tell which one is the infrared photo? I'm sure you can.
See you in the next post.
If you have an application that needs black materials or reflection control, tell us the reflectance and size you need and we will suggest the right grade.
Thin, low-shedding carbon foam sheet for visible to NIR stray light inside equipment. IR Flock Sheet
Flocked fabric with NIR dye and carbon-loaded fibers. Below 0.5% from 400 to 1500 nm.
Originally published in Japanese on March 18, 2019, and revised in September 2026. Translated into English in October 2026.
Related: The World of Near Infrared Light & Its Applications · What Is Reflectance? The Science Behind True Blackness
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